[test] OpenGL unit tests

This CL moves MyEGL/GLESv2/Dispatch into a more
general location---emugl_common---allowing
us to dispatch underlying GLESv2/EGL libs
from other places in the emulator than qt gl widget,
and introduces code for OpenGL unit tests,
along with a basic context creation unit tests.

We can now do offscreen-rendering type unit tests
with OpenGL. This is very helpful for debugging
host-side OpenGL issues, rather than going through
X11 / WGL from the ground up to repro OpenGL cases.

This should also be useful for testing snapshots.

Usage:

qemu dir -> cwd
DYLD_LIBRARY_PATH (or platform equivalent)=objs/lib64
objs/lib64OpenglRender_unittests --gtest_also_run_disabled_tests

should run at least basic context creation and dispatch.

Change-Id: If89966156bb4978a302fd94a96d77e5ce1552c03
diff --git a/host/libs/virglrenderer/OpenGLESDispatch/EGLDispatch.cpp b/host/libs/virglrenderer/OpenGLESDispatch/EGLDispatch.cpp
index db42c0b..fe0cbfb 100644
--- a/host/libs/virglrenderer/OpenGLESDispatch/EGLDispatch.cpp
+++ b/host/libs/virglrenderer/OpenGLESDispatch/EGLDispatch.cpp
@@ -33,12 +33,9 @@
     if (!s_egl.function_name || !s_egl.eglGetProcAddress) \
             RENDER_EGL_LOAD_FIELD(return_type, function_name, signature)
 
-bool init_egl_dispatch()
-{
-
+bool init_egl_dispatch() {
     const char *libName = getenv("ANDROID_EGL_LIB");
     if (!libName) libName = DEFAULT_EGL_LIB;
-
     char error[256];
     emugl::SharedLibrary *lib = emugl::SharedLibrary::open(libName, error, sizeof(error));
     if (!lib) {